FERMAT'S THEOREM

Published: October 31, 1993

2. Fermat honestly thought he had a direct proof, but he was wrong; in thinking it through, he had made a misstep and didn't realize it.

3. Fermat looked for a proof and couldn't construct one. Yet, he strongly believed the theorem was provable. Consequently, he wrote the marginal note as an implied challenge to mathematicians, present and future.

4. Fermat didn't have a proof, and he knew it. What we have here is a bit of 16th-century leg pulling. SEYMOUR V. POLLACK St. Louis